Backend API manual¶

VST Utils framework consolidates such frameworks as Django, Django Rest Framework, drf-yasg and Celery. Below are descriptions of some features used in the development of projects based on vstutils.

Models¶

A model is the single, definitive source of truth about your data. It contains the essential fields and behaviors of the data you’re storing. Usually best practice is to avoid writing views and serializers manually, BModel provides plenty of Meta attributes to autogenerate serializers and views for almost any usecase.

Default Django model classes overrides in vstutils.models module.

class vstutils.models.BModel(*args, **kwargs)[source]¶

Default model class that autogenerate model viewset, separate serializers for list() and retrieve(), filters, api endpoints and nested views.

Examples:

from django.db import models
from rest_framework.fields import ChoiceField
from vstutils.models import BModel

class Stage(BModel):
    name = models.CharField(max_length=256)
    order = models.IntegerField(default=0)

    class Meta:
        default_related_name = "stage"
        ordering = ('order', 'id',)
        # fields which would be showed on list.
        _list_fields = [
            'id',
            'name',
        ]
        # fields which would be showed on detail view and creation.
        _detail_fields = [
            'id',
            'name',
            'order'
        ]
        # make order as choices from 0 to 9
        _override_detail_fields = {
            'order': ChoiceField((str(i) for i in range(10)))
        }


class Task(BModel):
    name = models.CharField(max_length=256)
    stages = models.ManyToManyField(Stage)

    class Meta:
        # fields which would be showed.
        _list_fields = [
            'id',
            'name',
        ]
        # create nested views from models
        _nested = {
            'stage': {
                'allow_append': False,
                'model': Stage
            }
        }

In this case, you create models which could converted to simple view, where:

POST/GET to /api/version/task/ - creates new or get list of tasks
PUT/PATCH/GET/DELETE to /api/version/task/:id/ - updates, retrieves or removes instance of task
POST/GET to /api/version/task/:id/stage/ - creates new or get list of stages in task
PUT/PATCH/GET/DELETE to /api/version/task/:id/stage/:stage_id - updates, retrieves or removes instance of stage in task.

To attach a view to an API just insert the following code in settings.py:

API[VST_API_VERSION][r'task'] = {
    'model': 'your_application.models.Task'
}

For primary access to generated view, just inherit from Task.generated_view property.

List of meta-attributes for generating a view:

_view_class - list of additional view classes to inherit from, class or string to import with base class ViewSet. Constants are also supported:
- read_only - to create a view only for viewing;
- list_only - to create a view with list only;
- history - to create a view only for viewing and deleting records.
Default is simple CRUD-view.
_serializer_class - class of API serializer, use this attribute to specify parent class for autogenerated serializers. Default is vstutils.api.serializers.VSTSerializer. Can take a string to import, serializer class or django.utils.functional.SimpleLazyObject.
_serializer_class_name - model name for OpenAPI definitions.This would be a model name in generated admin interface. Default is name of model class.
_list_fields or _detail_fields - list of fields which will be listed in entity view. Same as DRF serializers meta-attribute “fields”.
_override_list_fields or _override_detail_fields - mapping with names and field types that will be redeclared in serializer attributes(think of it as you are redeclaring fields in DRF ModelSerializer).
_properties_groups - dict with key as group name and value as list with fields. Allows to grouping fields on frontend in cases.
_view_field_name - name of field which frontend should show as main view name.
_non_bulk_methods - list of methods which must not used via bulk requests.
_extra_serializer_classes - mapping with additional serializers in viewset. Example, custom serializer, which will compute smthg in action (mapping name). Value can be string for import. Important note: setting model attribute to None allows to use standard serializer generation mechanism and get fields from a list or detail serializer (set __inject_from__ serializer’s meta attribute to list or detail accordingly).
_filterset_fields - list/dict of filterset names for API-filtering. Default is list of fields in list view. When processing a list of fields, it checks for the presence of special field names and inherit additional parent classes. If the list contains id, class will inherit from vstutils.api.filters.DefaultIDFilter. If the list contains name, class will inherit from vstutils.api.filters.DefaultNameFilter. If both conditions are present, inheritance will be from all of the above classes. Possible values include list of fields to filter or dict where key is a field name and value is a Filter class. Dict extends attribute functionality and provide ability to override filter field class (None value disable overriding).
_filter_backends - list of vstutils.api.filter_backends.VSTFilterBackend classes. Values can be string for import.
_override_filter_backends - boolean flag indicates that _filter_backends override default viewset (otherwise appends). Default is False.
_permission_classes - list of DRF permission classes. Values can be string for import.
_override_permission_classes - boolean flag indicates that _permission_classes override default viewset (otherwise appends). Default is False.
_copy_attrs - list of model-instance attributes indicates that object is copiable with this attrs.
_nested - key-value mapping with nested views (key - nested name, kwargs for vstutils.api.decorators.nested_view decorator but supports model attribute as nested). model can be string for import.

Note

Sometimes you may need to create an action on generated view. Use vstutils.models.decorators.register_view_action decorator with the detail argument to determine applicability to a list or detail entry. In this case, the decorated method will take an instance of the view object as self attribute.

Note

In some cases, inheriting models may require inheriting the Meta class from the base model. If the Meta is explicitly declared in the base class, then you can get it through the attribute OriginalMeta and use it for inheritance.

Note

Docstring of model will be reused for view descriptions. You can specify both a general description for all actions and specifically for each action using the following syntax:

General description for all actions.

action_name:
    Description for this action.

another_action:
    Description for another action.

hidden¶: If hidden is set to True, entry will be excluded from query in BQuerySet.

id¶: Primary field for select and search in API.

class vstutils.models.Manager(*args, **kwargs)[source]¶: Default VSTUtils manager. Used by BaseModel and BModel. Uses BQuerySet as base.

class vstutils.models.queryset.BQuerySet(model=None, query=None, using=None, hints=None)[source]¶

Represent a lazy database lookup for a set of objects. Allows to override default iterable class by custom_iterable_class attribute (class with __iter__ method which returns generator of model objects) and default query class by custom_query_class attribute (class inherited from django.db.models.sql.query.Query).

cleared()[source]¶: Filter queryset for models with attribute ‘hidden’ and exclude all hidden objects.

get_paginator(*args, **kwargs)[source]¶: Returns initialized object of vstutils.utils.Paginator over current instance’s QuerySet. All args and kwargs passthroughs to Paginator’s constructor.

paged(*args, **kwargs)[source]¶: Returns paginated data with custom Paginator-class. By default, uses PAGE_LIMIT from global settings.

class vstutils.models.decorators.register_view_action(*args, **kwargs)[source]¶: Simple decorator for marking model methods as generated view actions. The decorated method becomes a method of generated view and self will be view object. See supported args in vstutils.api.decorators.subaction()

Note

Often, the action does not transfer any parameters and requires only sending an empty query. To speed up development, we set the default serializer to vstutils.api.serializers.EmptySerializer.

Also you can use custom models without using database:¶

class vstutils.custom_model.FileModel(*args, **kwargs)[source]¶

Simple custom model which load data from YAML-file. Path to the file stored in FileModel.file_path attribute.

Examples:

Source file stored in /etc/authors.yaml with content:

- name: "Sergey Klyuykov"
- name: "Michael Taran"

Correct usage will be:

from vstutils.custom_model import FileModel, CharField

class Authors(FileModel):
    name = CharField(max_length=512)

    file_path = '/etc/authors.yaml'

class vstutils.custom_model.ListModel(*args, **kwargs)[source]¶

Simple custom model which uses attribute ListModel.data with dicts of models data. Usefull when you have simple list of data.

Examples:

from vstutils.custom_model import ListModel, CharField


class Authors(ListModel):
    name = CharField(max_length=512)

    data = [
        {"name": "Sergey Klyuykov"},
        {"name": "Michael Taran"},
    ]

data = []¶: List with data dicts. Empty by default.

Web API¶

Web API is based on Django Rest Framework with some nested functions.

Fields¶

The Framework includes a list of convenient serializer fields. Some of them take effect only in generated admin interface.

Additional serializer fields for generating OpenAPI and GUI.

class vstutils.api.fields.AutoCompletionField(*args, **kwargs)[source]¶

Field that provides autocompletion on frontend, using specified list of objects.

Parameters

autocomplete (list,tuple,str) – Autocompletion reference. You can set simple list/tuple with values or set OpenApi schema definition name. For definition name GUI will find optimal link and will show values based on autocomplete_property and autocomplete_represent arguments.
autocomplete_property (str) – this argument indicates which attribute will be get from OpenApi schema definition model as value.
autocomplete_represent – this argument indicates which attribute will be get from OpenApi schema definition model as represent value.

Note

Take effect only in GUI. In API it would behave as VSTCharField.

class vstutils.api.fields.BinFileInStringField(*args, **kwargs)[source]¶: Field extends FileInStringField, but work with binary(base64) files.

Note

Take effect only in GUI. In API it would behave as VSTCharField.

class vstutils.api.fields.CommaMultiSelect(*args, **kwargs)[source]¶

Field containing a list of values with specified separator(default: “,”). Gets list of values from another model or custom list. Provides autocompletion as AutoCompletionField, but with comma-lists. Suited for property-fields in model where main logic is already implemented or with CharField.

Parameters

select (str,tuple,list) – OpenApi schema definition name or list with values.
select_separator (str) – separator of values. Default is comma.
select_property,select_represent – work as autocomplete_property and autocomplete_represent. Default is name.
use_prefetch – prefetch values on frontend at list-view. Default is False.
make_link – Show value as link to model. Default is True.
dependence (dict) – Dictionary, where keys are name of field from the same model, and values are name of query filter .If at least one of the fields that we depend on is non nullable, required and set to null, autocompletion list will be empty and field will be disabled.

Note

Take effect only in GUI. In API it would behave as VSTCharField.

class vstutils.api.fields.DependEnumField(*args, **kwargs)[source]¶

Field extends DynamicJsonTypeField but data won’t be transformed to json and would be given as is. Useful for property in models or for actions.

Parameters

field (str) – field in model which value change will change type of current value.
types – key-value mapping where key is value of subscribed field and value is type (in OpenApi format) of current field.
choices (dict) – variants of choices for different subscribed field values. Uses mapping where key is value of subscribed field and value is list with values to choice.

Note

Take effect only in GUI. In API it would behave as VSTCharField but without value modifications.

class vstutils.api.fields.DependFromFkField(*args, **kwargs)[source]¶

Field extends DynamicJsonTypeField. Validates field data by field_attribute chosen in related model. By default, any value of field_attribute validates as VSTCharField. To override this behavior you should set dict-attribute in related model named {field_attribute value}_fields_mapping where:

key - string representation of value type which is received from related instance field_attribute.
value - rest_framework.Field instance for validation.

Parameters

field (str) – field in model which value change will change type of current value. Field must be FkModelField.
field_attribute (str) – attribute of model related model instance with name of type.

Warning

field_attribute in related model must be rest_framework.ChoicesField or GUI will show field as simple text.

class vstutils.api.fields.DynamicJsonTypeField(*args, **kwargs)[source]¶

Field which type is based on another field. It converts value to internal string and represent field as json object.

Parameters

field (str) – field in model which value change will change type of current value.
types – key-value mapping where key is value of subscribed field and value is type (in OpenApi format) of current field.
choices (dict) – variants of choices for different subscribed field values. Uses mapping where key is value of subscribed field and value is list with values to choice.

Note

Take effect only in GUI. In API it would behave as VSTCharField but without value modifications.

class vstutils.api.fields.FileInStringField(*args, **kwargs)[source]¶

Field extends VSTCharField and saves file’s content as string.

Value must be text (not binary) and saves in model as is.

Note

Take effect only in GUI. In API it would behave as VSTCharField.

class vstutils.api.fields.FkField(*args, **kwargs)[source]¶

Implementation of ForeignKeyField.You can specify which field of a related model will be stored in field(default: “id”), and which will represent field on frontend.

Parameters

select (str) – OpenApi schema definition name.
autocomplete_property (str) – this argument indicates which attribute will be get from OpenApi schema definition model as value. Default is id.
autocomplete_represent – this argument indicates which attribute will be get from OpenApi schema definition model as represent value. Default is name.
use_prefetch (bool) – prefetch values on frontend at list-view. Default is True.
make_link (bool) – Show value as link to model. Default is True.
dependence (dict) – Dictionary, where keys are name of field from the same model, and keys are name of query filter. If at least one of the fields that we depend on is non nullable, required and set to null, autocompletion list will be empty and field will be disabled.

Note

Take effect only in GUI. In API it would behave as rest_framework.IntegerField.

class vstutils.api.fields.FkModelField(*args, **kwargs)[source]¶

Extends FkField, but stores referred model class. This field is useful for django.db.models.ForeignKey fields in model to set.

Parameters

select (vstutils.models.BModel,vstutils.api.serializers.VSTSerializer) – model class (based on vstutils.models.BModel) or serializer class which used in API and has path in OpenApi schema.
autocomplete_property (str) – this argument indicates which attribute will be get from OpenApi schema definition model as value. Default is id.
autocomplete_represent – this argument indicates which attribute will be get from OpenApi schema definition model as represent value. Default is name.
use_prefetch – prefetch values on frontend at list-view. Default is True.
make_link – Show value as link to model. Default is True.

Warning

Model class on call .to_internal_value get object from database. Be careful on mass save executions.

Warning

Permissions to model which is referred by this field, will not be checked. You should check it manually in signals or validators.

class vstutils.api.fields.HtmlField(*args, **kwargs)[source]¶: Field contains html text and marked as format:html. The field does not validate whether its content is HTML.

Warning

Do not allow for users to modify this data because they can set some scripts to value and it would be vulnerability.

Note

Take effect only in GUI. In API it would behave as VSTCharField.

class vstutils.api.fields.MultipleNamedBinaryFileInJsonField(*args, **kwargs)[source]¶: Extends NamedBinaryFileInJsonField but uses list of structures. Used for operating with multiple files.

class vstutils.api.fields.MultipleNamedBinaryImageInJsonField(*args, **kwargs)[source]¶: Extends MultipleNamedBinaryFileInJsonField but uses list of structures. Used for operating with multiple images and works as list of NamedBinaryImageInJsonField.

class vstutils.api.fields.NamedBinaryFileInJsonField(*args, **kwargs)[source]¶

Field that takes JSON with properties: * name - string - name of file; * mediaType - string - MIME type of file * content - base64 string - content of file.

This field is useful for saving binary files with their names in django.db.models.CharField or django.db.models.TextField model fields. All manipulations with decoding and encoding binary content data executes on client. This imposes reasonable limits on file size.

Note

Take effect only in GUI. In API it would behave as VSTCharField with structure of data.

class vstutils.api.fields.NamedBinaryImageInJsonField(*args, **kwargs)[source]¶: Extends NamedBinaryFileInJsonField but in GUI has a different view which shows an image(if inputed binary image is valid).Validation of this field can be done with vstutils.api.validators.ImageValidator.

class vstutils.api.fields.PasswordField(*args, **kwargs)[source]¶: Extends CharField but in schema overload format to password. Used for making fields with asterisks instead of data in GUI.

class vstutils.api.fields.RatingField(min_value=0, max_value=5, step=1, front_style='stars', **kwargs)[source]¶

Extends class ‘rest_framework.serializers.FloatField’. This field represents a rating form input on frontend. Grading limits can be specified with ‘min_value=’ and ‘max_value=’, defaults are 0 to 5.Minimal step between grades are specified in ‘step=’, default - 1.Frontend visual representation can be chosen with ‘front_style=’, available variants are listed in ‘self.valid_front_styles’.

for ‘slider’ front style, you can specify slider color, by passing valid color to ‘color=’. for ‘fa_icon’ front style, you can specify FontAwesome icon that would be used for displaying rating, by passing a valid FontAwesome icon code to ‘fa_class=’.

Parameters

min_value (float, int) – minimal level
max_value (float, int) – maximal level
step (float, int) – minimal step between levels
front_style (str) – visualization on frontend field. Allowed: [‘stars’, ‘slider’, ‘fa_icon’].
color (str) – color of rating element (star, icon or slider) in css format
fa_class (str) – FontAwesome icon code

class vstutils.api.fields.RedirectCharField(*args, **kwargs)[source]¶: Field for redirect by string. Often used in actions for redirect after execution.

Note

Take effect only in GUI. In API it would behave as rest_framework.IntegerField.

class vstutils.api.fields.RedirectIntegerField(*args, **kwargs)[source]¶: Field for redirect by id. Often used in actions for redirect after execution.

Note

Take effect only in GUI. In API it would behave as rest_framework.IntegerField.

class vstutils.api.fields.RelatedListField(related_name, fields, view_type='list', **kwargs)[source]¶

Extends class ‘vstutils.api.fields.VSTCharField’. With this field you can output reverse ForeignKey relation as a list of related instances. To use it, you need to specify ‘related_name’ kwarg(related_manager for reverse ForeignKey) and ‘fields’ kwarg(list or tuple of fields from related model, which needs to be included)

Parameters

related_name (str) – name of a related manager for reverse foreign key
fields (list[str], tuple[str]) – list of related model fields.
view_type (str) – Determines how field should be shown on frontend. Must be either ‘list’ or ‘table’.

class vstutils.api.fields.SecretFileInString(*args, **kwargs)[source]¶

Field extends FileInStringField, but hides it’s value in admin interface.

Value must be text (not binary) and saves in model as is.

Note

Take effect only in GUI. In API it would behave as VSTCharField.

class vstutils.api.fields.TextareaField(*args, **kwargs)[source]¶: Field containing multiline string.

Note

Take effect only in GUI. In API it would behave as VSTCharField.

class vstutils.api.fields.UptimeField(*args, **kwargs)[source]¶: Field for some uptime(time duration), in seconds, for example.

Note

Take effect only in GUI. In API it would behave as rest_framework.IntegerField.

class vstutils.api.fields.VSTCharField(*args, **kwargs)[source]¶: Simple CharField (extends rest_framework.fields.CharField). This field translate any json type to string for model.

Validators¶

There is useful validation classes for fields.

class vstutils.api.validators.ImageBaseSizeValidator(extensions=None, **kwargs)[source]¶

If you want you want to use this class for validating image width/height, you should rewrite self.orientation to (‘height’,) or (‘width’,) or (‘height’, ‘width’)

Raises rest_framework.exceptions.ValidationError: if not(min <= (height or width) <= max)

Parameters: extensions (typing.Union[typing.Tuple, typing.List, None]) –

class vstutils.api.validators.ImageHeightValidator(extensions=None, **kwargs)[source]¶

Wrapper for _ImageBaseSizeValidator that validates only height

Parameters

min_height – minimal height of an image being validated
max_height – maximal height of an image being validated
extensions (typing.Union[typing.Tuple, typing.List, None]) –

class vstutils.api.validators.ImageOpenValidator(extensions=None, **kwargs)[source]¶

Image validator that checks if image can be unpacked from b64 to PIL Image obj

Raises rest_framework.exceptions.ValidationError: in case PIL throws error when trying to open given file

Parameters: extensions (typing.Union[typing.Tuple, typing.List, None]) –

class vstutils.api.validators.ImageResolutionValidator(extensions=None, **kwargs)[source]¶

Wrapper for _ImageBaseSizeValidator that validates both height and width

Parameters

min_height – minimal height of an image being validated
max_height – maximal height of an image being validated
min_width – minimal width of an image being validated
max_width – maximal width of an image being validated
extensions (typing.Union[typing.Tuple, typing.List, None]) –

class vstutils.api.validators.ImageValidator(extensions=None, **kwargs)[source]¶

Base Image Validation class Validates image format Wont work if Pillow isn’t installed :type extensions: typing.Union[typing.Tuple, typing.List, None] :param extensions: Tuple or List of file extensions, that should pass the validation Raises rest_framework.exceptions.ValidationError: in case file extension are not in the list

property has_pillow¶: Check if Pillow is installed

class vstutils.api.validators.ImageWidthValidator(extensions=None, **kwargs)[source]¶

Wrapper for _ImageBaseSizeValidator that validates only height

Parameters

min_width – minimal width of an image being validated
max_width – maximal width of an image being validated
extensions (typing.Union[typing.Tuple, typing.List, None]) –

class vstutils.api.validators.RegularExpressionValidator(regexp=None)[source]¶

Class for regular expression based validation

Raises: rest_framework.exceptions.ValidationError – in case value does not match regular expression
Parameters: regexp (typing.Optional[typing.Pattern]) –

class vstutils.api.validators.UrlQueryStringValidator(regexp=None)[source]¶

Class for validation url query string, for example a=&b=1

Parameters: regexp (typing.Optional[typing.Pattern]) –

Serializers¶

Default serializer classes for web-api. Read more in Django REST Framework documentation for Serializers.

class vstutils.api.serializers.BaseSerializer(*args, **kwargs)[source]¶: Default and simple serializer with default logic to work with objects. Read more in DRF documentation how to create Serializers and work with them.

class vstutils.api.serializers.EmptySerializer(*args, **kwargs)[source]¶: Default serializer for empty responses. In generated GUI this means simple action button which will not show additional view before execution.

class vstutils.api.serializers.VSTSerializer(*args, **kwargs)[source]¶: Default model serializer based on rest_framework.serializers.ModelSerializer. Read more in DRF documentation how to create Model Serializers.

Views¶

Default ViewSets for web-api.

class vstutils.api.base.CopyMixin(**kwargs)[source]¶

Mixin for viewsets which adds copy endpoint to view.

copy(request, **kwargs)[source]¶

Endpoint which copy instance with deps.

Parameters: request (rest_framework.request.Request) –
Return type: vstutils.api.responses.BaseResponseClass

copy_field_name = 'name'¶: Name of field which will get a prefix.

copy_prefix = 'copy-'¶: Value of prefix which will be added to new instance name.

copy_related: Iterable[str] = ()¶: List of related names which will be copied to new instance.

class vstutils.api.base.HistoryModelViewSet(**kwargs)[source]¶: Default viewset like ReadOnlyModelViewSet but for historical data (allow to delete, but cannt create and update).

class vstutils.api.base.ModelViewSet(**kwargs)[source]¶

A viewset that provides default create(), retrieve(), update(), partial_update(), destroy() and list() actions under model.

Variables

model (vstutils.models.BModel) – DB model with data.
serializer_class (vstutils.api.serializers.VSTSerializer) – Serializer for view of Model data.
serializer_class_one (vstutils.api.serializers.VSTSerializer) – Serializer for view one instance of Model data.
serializer_class_[ACTION_NAME] (vstutils.api.serializers.VSTSerializer) – Serializer for view of any endpoint like .create.

Examples:

from vstutils.api.base import ModelViewSet
from . import serializers as sers


class StageViewSet(ModelViewSet):
    # This is difference with DRF:
    # we use model instead of queryset
    model = sers.models.Stage
    # Serializer for list view (view for a list of Model instances
    serializer_class = sers.StageSerializer
    # Serializer for page view (view for one Model instance).
    # This property is not required, if its value is the same as `serializer_class`.
    serializer_class_one = sers.StageSerializer
    # Allowed to set decorator to custom endpoint like this:
    # serializer_class_create - for create method
    # serializer_class_copy - for detail endpoint `copy`.
    # etc...

class vstutils.api.base.ReadOnlyModelViewSet(**kwargs)[source]¶: Default viewset like vstutils.api.base.ModelViewSet for readonly models.

class vstutils.api.decorators.nested_view(name, arg=None, methods=None, *args, **kwargs)[source]¶

By default DRF does not support nested views. This decorator solves this problem.

You need two or more models with nested relationship (Many-to-Many or Many-to-One) and two viewsets. Decorator setups nested viewset to parent viesetclass and generate paths in API.

Parameters

name (str) – – Name of nested path. Also used as default name for related queryset (see manager_name).
arg (str) – – Name of nested primary key field.
view (vstutils.api.base.ModelViewSet, vstutils.api.base.HistoryModelViewSet, vstutils.api.base.ReadOnlyModelViewSet) – – Nested viewset class.
allow_append (bool) – – Flag for allowing to append existed instances.
manager_name (str) – – Name of model-object attr which contains nested queryset.
methods (list) – – List of allowed methods to nested view endpoints.
subs (list,None) – – List of allowed subviews or actions to nested view endpoints.

Example:

from vstutils.api.decorators import nested_view
from vstutils.api.base import ModelViewSet
from . import serializers as sers


class StageViewSet(ModelViewSet):
    model = sers.models.Stage
    serializer_class = sers.StageSerializer


nested_view('stages', 'id', view=StageViewSet)
class TaskViewSet(ModelViewSet):
    model = sers.models.Task
    serializer_class = sers.TaskSerializer

This code generates api paths:

/tasks/ - GET,POST

/tasks/{id}/ - GET,PUT,PATCH,DELETE

/tasks/{id}/stages/ - GET,POST

/tasks/{id}/stages/{stages_id}/ - GET,PUT,PATCH,DELETE

vstutils.api.decorators.subaction(*args, **kwargs)[source]¶

Decorator which wrap object method to subaction of viewset.

Parameters

methods (list) – List of allowed HTTP-request methods. Default is ["post"].
detail (bool) – Flag which signalizing that this method is over one instance.
serializer_class (vstutils.api.serializers.VSTSerializer) – Serializer for this action.
permission_classes – Tuple or list permission classes.
url_path (str) – API-path name for this action.
description (str) – Description for this action in OpenAPI.
multiaction (bool) – Allow to use this action in multiactions. Works only with vstutils.api.serializers.EmptySerializer as response.

Filtersets¶

For greater development convenience, the framework provides additional classes and functions for filtering elements by fields.

class vstutils.api.filters.DefaultIDFilter(data=None, queryset=None, *, request=None, prefix=None)[source]¶: Basic filterset to search by id. Provides a search for multiple values separated by commas. Uses extra_filter() in fields.

class vstutils.api.filters.DefaultNameFilter(data=None, queryset=None, *, request=None, prefix=None)[source]¶: Basic filterset to search by part of name. Uses LIKE DB condition by name_filter().

class vstutils.api.filters.FkFilterHandler(related_pk='id', related_name='name', pk_handler=<class 'int'>)[source]¶

Simple handler for filtering by relational fields.

Parameters

related_pk (str) – Field name of related model’s primary key. Default is ‘id’.
related_name (str) – Field name of related model’s charfield. Default is ‘name’.
pk_handler (typing.Callable) – Changes handler for checking value before search. Sends “0” in handler falls. Default is ‘int()’.

Example:

class CustomFilterSet(filters.FilterSet):
    author = CharFilter(method=vst_filters.FkFilterHandler(related_pk='pk', related_name='email'))

Where author is ForeignKey to User and you want to search by primary key and email.

vstutils.api.filters.extra_filter(queryset, field, value)[source]¶

Method for searching values in a comma-separated list.

Parameters

queryset (django.db.models.query.QuerySet) – model queryset for filtration.
field (str) – field name in FilterSet. Also supports __not suffix.
value (str) – comma separated list of searching values.

Returns

filtered queryset.

Return type

django.db.models.query.QuerySet

vstutils.api.filters.name_filter(queryset, field, value)[source]¶

Method for searching by part of name. Uses LIKE DB condition or contains qs-expression.

Parameters

queryset (django.db.models.query.QuerySet) – model queryset for filtration.
field (str) – field name in FilterSet. Also supports __not suffix.
value (str) – searching part of name.

Returns

filtered queryset.

Return type

django.db.models.query.QuerySet

Responses¶

DRF provides a standard set of variables whose names correspond to the human-readable name of the HTTP code. For convenience, we have dynamically wrapped this in a set of classes that have appropriate names and additionally provide the following capabilities:

String responses are wrapped in json like { "detail": "string response" }.
Keep attribute timings for further processing in middlewares.
Set status code from class name (e.g. HTTP_200_OK or Response200 got code 200).

All classes inherit from:

class vstutils.api.responses.BaseResponseClass(*args, **kwargs)[source]¶

API response class with default status code.

Variables

status_code (int) – HTTP status code.
timings (int,None) – Response timings.

Parameters

timings – Response timings.

Middlewares¶

By default, the Django assumes that the developer will develop itself Middleware class, but it is not always convenient. The vstutils library offers a convenient request handler class for elegant OOP development. Middlewares is needed to process incoming requests and sent responses before they reach the final destination.

class vstutils.middleware.BaseMiddleware(get_response)[source]¶

Middleware base class for handling:

Incoming requests by BaseMiddleware.request_handler();
Outgoing response before any calling on server by BaseMiddleware.get_response_handler();
Outgoing responses by BaseMiddleware.handler().

Middleware must be added to MIDDLEWARE list in settings.

Example:

from vstutils.middleware import BaseMiddleware
from django.http import HttpResponse


class CustomMiddleware(BaseMiddleware):
    def request_handler(self, request):
        # Add header to request
        request.headers['User-Agent'] = 'Mozilla/5.0'
        return request

    def get_response_handler(self, request):
        if not request.user.is_stuff:
            # Return 403 HTTP status for non-stuff users.
            # This request never gets in any view.
            return HttpResponse(
                "Access denied!",
                content_type="text/plain",
                status_code=403
            )
        return super().get_response_handler(request)

    def handler(self, request, response):
        # Add header to response
        response['Custom-Header'] = 'Some value'
        return response

Parameters: get_response (typing.Callable) –

get_response_handler(request)[source]¶

Entrypoint for breaking or continuing request handling. This function should return django.http.HttpResponse object or result of parent class calling.

Parameters: request (django.http.HttpRequest) – HTTP-request object which is wrapped from client request.
Return type: django.http.HttpResponse

handler(request, response)[source]¶

The response handler. Here, all the magic of processing the response sent, insertion of headers to response, etc.

Parameters

request (django.http.HttpRequest) – HTTP-request object.
response (django.http.HttpResponse) – HTTP-response object which will be sended to client.

Returns

Handled response object.

Return type

django.http.HttpResponse

request_handler(request)[source]¶

The request handler. Called before request will be handled by any view.

Parameters: request (django.http.HttpRequest) – HTTP-request object which is wrapped from client request.
Returns: Handled request object.
Return type: django.http.HttpRequest

Endpoint¶

Endpoint view has two purposes: bulk requests execution and providing openapi schema.

Endpoint url is /{API_URL}/endpoint/, for example value with default settings is /api/endpoint/.

API_URL can be changed in settings.py.

class vstutils.api.endpoint.EndpointViewSet(**kwargs)[source]¶

Default API-endpoint viewset.

get(request)[source]¶

Returns response with swagger ui or openapi json schema if ?format=openapi

Parameters: request (vstutils.api.endpoint.BulkRequestType) –
Return type: django.http.response.HttpResponse

get_client(request)[source]¶

Returns test client and guarantees that if bulk request comes authenticated than test client will be authenticated with the same user

Parameters: request (vstutils.api.endpoint.BulkRequestType) –
Return type: vstutils.api.endpoint.BulkClient

get_serializer(*args, **kwargs)[source]¶

Return the serializer instance that should be used for validating and deserializing input, and for serializing output.

Return type: vstutils.api.endpoint.OperationSerializer

get_serializer_context(context)[source]¶

Extra context provided to the serializer class.

Return type: dict

operate(operation_data, context)[source]¶

Method used to handle one operation and return result of it

Parameters

operation_data (typing.Dict) –
context (typing.Dict) –

Return type

typing.Tuple[typing.Dict, typing.SupportsFloat]

post(request)[source]¶

Execute transactional bulk request

Parameters: request (vstutils.api.endpoint.BulkRequestType) –
Return type: vstutils.api.responses.BaseResponseClass

put(request, allow_fail=True)[source]¶

Execute non transaction bulk request

Parameters: request (vstutils.api.endpoint.BulkRequestType) –
Return type: vstutils.api.responses.BaseResponseClass

serializer_class¶

One operation serializer class.

alias of vstutils.api.endpoint.OperationSerializer

versioning_class¶: alias of rest_framework.versioning.QueryParameterVersioning

Bulk requests¶

Bulk request allows you send multiple request to api at once, it accepts json list of operations.

Method	Transactional (all operations in one transaction)	Synchronous (operations executed one by one in given order)
`PUT /{API_URL}/endpoint/`	NO	YES
`POST /{API_URL}/endpoint/`	YES	YES
`PATCH /{API_URL}/endpoint/`	NO	NO

Parameters of one operation (^* means that parameter is required):

method^* - http method of request
path^* - path of request, can be str or list
data - data that needs to be sent
query - query parameters as str
headers - dict with headers which will be sent, names of headers must follow CGI specification (e.g., CONTENT_TYPE, GATEWAY_INTERFACE, HTTP_*).
version - str with specified version of api, if not provided then VST_API_VERSION will be used

In any request parameter you can insert result value of previous operations (<<{OPERATION_NUMBER}[path][to][value]>>), for example:

[
    {"method": "post", "path": "user", "data": {"name": "User 1"}),
    {"method": "delete", "version": "v2", "path": ["user", "<<0[data][id]>>"]}
]

Result of bulk request is json list of objects for operation:

method - http method
path - path of request, always str
data - data that needs to be sent
status - response status code

Transactional bulk request returns 502 BAG GATEWAY and make rollback if one of requests is failed.

Warning

If you send non-transactional bulk request, you will get 200 status and must validate statuses on each operation responses.

Openapi schema¶

Request on GET /{API_URL}/endpoint/ returns Swagger UI.

Request on GET /{API_URL}/endpoint/?format=openapi returns json openapi schema. Also you can specify required version of schema using version query parameter (e.g., GET /{API_URL}/endpoint/?format=openapi&version=v2).

Applying hooks to the schema can also be helpful. This functionality will help to change certain data in the schema before it will be sended to user. In order to set some hooks, it is enough to specify in settings.py the OPENAPI_HOOKS which is an array with lines for importing functions. Each function will take 2 named arguments:

request - user request object.
schema - ordered dict with openapi schema.

Note

Sometimes hooks may raise an exception, and in order not to break the chain of data modification, such exceptions are handled. However, the changes made to the schema before the raised exception will be saved.

Example hook:

def hook_add_username_to_guiname(request, schema):
    schema['info']['title'] = f"{request.username} - {schema['info']['title']}"

Testing Framework¶

VST Utils Framework includes a few helper in base testcase class and improve support for making API requests. That means if you want make bulk request to endpoint you dont need create and init test client, but just need to call:

endpoint_results = self.bulk([
    # list of endpoint requests
])

Creating test case¶

After creating new project via vstutils you can found test.py module, where you see testcase classes based on vstutils.tests.BaseTestCase. At the moment, we officially support two styles of writing tests: through classic and simple query wrappers with run check and through runtime optimized bulk queries with manual value checking.

Simple example with classic tests¶

For example, if you have api endpoint like /api/v1/project/ and model Project you can write testcase like this:

from vstutils.tests import BaseTestCase


class ProjectTestCase(BaseTestCase):
    def setUp(self):
        super(ProjectTestCase, self).setUp()
        # init demo project
        self.initial_project = self.get_model_class('project.Test').objects.create(name="Test")

    def tearDown(self)
        super(ProjectTestCase, self).tearDown()
        # remove it after test
        self.initial_project.delete()

    def test_project_endpoint(self):
        # Test checks that api return valid values
        self.list_test('/api/v1/project/', 1)
        self.details_test(
            ["project", self.initial_project.id],
            name=self.initial_project.name
        )
        # Try to create new projects and check list endpoint
        test_data = [
            {"name": f"TestProject{i}"}
            for i in range(2)
        ]
        id_list = self.mass_create("/api/v1/project/", test_data, 'name')
        self.list_test('/api/v1/project/', 1 + len(id_list))

This simple example demonstrate functionality of default test case class. Default projects are initialized in such a way that for the fastest and most efficient result it is best to distribute testing of various entities into different classes. This example demonstrate classic style of testing, but you can use bulks in your test cases.

Bulk requests in tests¶

The bulk query system and its capabilities are very well suited for testing and executing valid queries. Returning to the previous example, it could be rewritten as follows:

from vstutils.tests import BaseTestCase


class ProjectTestCase(BaseTestCase):
    def setUp(self):
        super(ProjectTestCase, self).setUp()
        # init demo project
        self.initial_project = self.get_model_class('project.Test').objects.create(name="Test")

    def tearDown(self)
        super(ProjectTestCase, self).tearDown()
        # remove it after test
        self.initial_project.delete()

    def test_project_endpoint(self):
        test_data = [
            {"name": f"TestProject{i}"}
            for i in range(2)
        ]
        bulk_data = [
            {"method": "get", "path": ["project"]},
            {"method": "get", "path": ["project", self.initial_project.id]}
        ]
        bulk_data += [
            {"method": "post", "path": ["project"], "data": i}
            for i in test_data
        ]
        bulk_data.append(
            {"method": "get", "path": ["project"]}
        )
        results = self.bulk_transactional(bulk_data)

        self.assertEqual(results[0]['status'], 200)
        self.assertEqual(results[0]['data']['count'], 1)
        self.assertEqual(results[1]['status'], 200)
        self.assertEqual(results[1]['data']['name'], self.initial_project.name)

        for pos, result in enumerate(results[2:-1]):
            self.assertEqual(result['status'], 201)
            self.assertEqual(result['data']['name'], test_data[pos]['name'])

        self.assertEqual(results[-1]['status'], 200)
        self.assertEqual(results[-1]['data']['count'], 1 + len(test_data))

In this case, you have more code rows, but your tests will be closer to GUI workflow, because vstutils-projects uses /api/endpoint/ for requests. Either way, bulk queries are much faster due to some optimizations, so you can reduce testcase execution time.

Test case API¶

class vstutils.tests.BaseTestCase(methodName='runTest')[source]¶

Main testcase class extends django.test.TestCase.

assertCheckDict(first, second, msg=None)[source]¶

Fail if the two fields in dicts are unequal as determined by the ‘==’ operator. Checks if first not contains or not equal field in second

Parameters

first (typing.Dict) –
second (typing.Dict) –
msg (typing.Optional[str]) –

assertCount(iterable, count, msg=None)[source]¶

Call len() over iterable and check equals with count.

Parameters

iterable (typing.Sized) – any iterable object which could be sended to len().
count (int) – expected result.
msg (typing.Optional[typing.Any]) – error message

assertRCode(resp, code=200, *additional_info)[source]¶

Fail if response code is not equal. Message is response body.

Parameters

resp (django.http.HttpResponse) – response object
code (int) – expected code

bulk(data, code=200, **kwargs)[source]¶

Make non transactional bulk request and assert status code (default is 200)

Parameters

data (typing.Union[typing.List[typing.Dict[str, typing.Any]], str]) – request data
code (int) – http status to assert
kwargs – named arguments for get_result()

Return type

typing.Union[typing.List[typing.Dict[str, typing.Any]], str, typing.Dict, typing.Sequence[typing.Union[typing.List[typing.Dict[str, typing.Any]], str]]]

Returns

bulk response

bulk_transactional(data, code=200, **kwargs)[source]¶

Make transactional bulk request and assert status code (default is 200)

Parameters

data (typing.Union[typing.List[typing.Dict[str, typing.Any]], str]) – request data
code (int) – http status to assert
kwargs – named arguments for get_result()

Return type

typing.Union[typing.List[typing.Dict[str, typing.Any]], str, typing.Dict, typing.Sequence[typing.Union[typing.List[typing.Dict[str, typing.Any]], str]]]

Returns

bulk response

details_test(url, **kwargs)[source]¶

Test for get details of model. If you setup additional named arguments, the method check their equality with response data. Uses get_result() method.

Parameters

url – url to detail record. For example: /api/v1/project/1/ (where 1 is uniq id of project). You can use get_url() for building url.
kwargs – params that’s should be checked (key - field name, value - field value).

endpoint_call(data=None, method='get', code=200, **kwargs)[source]¶

Make request to endpoint and assert response status code if specified (default is 200). Uses get_result() method for execution.

Parameters

data (typing.Union[typing.List[typing.Dict[str, typing.Any]], str, None]) – request data
method (str) – http request method
code (int) – http status to assert

Return type

typing.Union[typing.List[typing.Dict[str, typing.Any]], str, typing.Dict, typing.Sequence[typing.Union[typing.List[typing.Dict[str, typing.Any]], str]]]

Returns

bulk response

get_count(model, **kwargs)[source]¶

Simple wrapper over get_model_filter() which returns counter of items.

Parameters

model (str,django.db.models.Model) – string which contains model name (if attribute model is set to the testcase class), module import, app.ModelName or django.db.models.Model.
kwargs – named arguments to django.db.models.query.QuerySet.filter().

Returns

number of instances in database.

Return type

int

get_model_class(model)[source]¶

Getting model class by string or return model arg.

Parameters: model (str,django.db.models.Model) – string which contains model name (if attribute model is set to the testcase class), module import, app.ModelName or django.db.models.Model.
Returns: Model class.
Return type: django.db.models.Model

get_model_filter(model, **kwargs)[source]¶

Simple wrapper over get_model_class() which returns filtered queryset from model.

Parameters

model (str,django.db.models.Model) – string which contains model name (if attribute model is set to the testcase class), module import, app.ModelName or django.db.models.Model.
kwargs – named arguments to django.db.models.query.QuerySet.filter().

Return type

django.db.models.query.QuerySet

get_result(rtype, url, code=None, *args, **kwargs)[source]¶

Execute and test response code on request with returning parsed result of request. The method uses the following procedure:

Test client authorization (with user which creates in setUp()).
Executing a request (sending args and kwargs to request method).
Parsing the result (converts json string to python-object).
Checking the http status code with assertRCode() (if you have not specified it, the code will be selected in accordance with the request method from the standard set std_codes).
Logout client.
Return parsed result.

Parameters

rtype – request type (methods from Client cls): get, post etc.
url – requested url string or tuple for get_url(). You can use get_url() for url building or setup it as full string.
code (typing.Optional[int]) – expected return code from request.
relogin – execute force login and logout on each call. Default is True.
args – extra-args for Client class request method.
kwargs – extra-kwargs for Client class request method.

Return type

typing.Union[typing.List[typing.Dict[str, typing.Any]], str, typing.Dict, typing.Sequence[typing.Union[typing.List[typing.Dict[str, typing.Any]], str]]]

Returns

result of request.

get_url(*items)[source]¶

Function for creating url path based on VST_API_URL and VST_API_VERSION settings. Without arguments returns path to default version of api.

Return type: str
Returns: string like /api/v1/.../.../ where ... is args of function.

list_test(url, count)[source]¶

Test for get list of models. Checks only list count. Uses get_result() method.

Parameters

url – url to abstract layer. For example: /api/v1/project/. You can use get_url() for building url.
count – count of objects in DB.

mass_create(url, data, *fields, **kwargs)[source]¶

Mass creation objects in api-abstration. Uses get_result() method.

Parameters

url – url to abstract layer like argument in get_result(). For example: /api/v1/project/.
data – list with data to send on creation and feature checks.
kwargs – extra-kwargs for request method.

Params fields

list of fields to check after creation.

Returns

list of id from all resulted objects.

Return type

list

Note

The method does not use endpoint requests. That mean if you want send some extra headers or data you can do it by additional kwargs.

models = None¶: Attribute with default project models module.

classmethod patch(*args, **kwargs)[source]¶

Simple unittest.mock.patch() class-method wrapper.

Return type: typing.AbstractContextManager[unittest.mock.Mock]

random_name()[source]¶

Simple function which returns uuid1 string.

Return type: str

std_codes: Dict[str, int] = {'delete': 204, 'get': 200, 'patch': 200, 'post': 201}¶: Default http status codes for different http methods. Uses in get_result()

class user_as(testcase, user)[source]¶

Context for execute bulk or something as user. The context manager overrides self.user in TestCase and revert this changes on exit.

Parameters: user (django.contrib.auth.models.AbstractUser) – new user object for execution.

Utils¶

This is some tested set of development utilities. Utilities include a collection of some code that will be useful in one way or another to develop the application. Most of the functions are used by vstutils itself.

class vstutils.utils.BaseEnum(value)[source]¶

BaseEnum extends Enum class and used to create enum-like objects that can be used in django serializers or django models.

Example:

from vstutils.models import BModel

class ItemCLasses(BaseEnum):
    FIRST='FIRST'
    SECOND='SECOND'
    THIRD='THIRD'


class MyDjangoModel(BModel):
    item_class = models.CharField(max_length=1024, choices=ItemCLasses.to_choices())

    @property
    def is_second(self):
        # Function check is item has second class of instance
        return ItemCLasses.SECOND.is_equal(self.item_class)

class vstutils.utils.BaseVstObject[source]¶

Default mixin-class for custom objects which needed to get settings and cache.

classmethod get_django_settings(name, default=None)[source]¶

Get params from Django settings.

Parameters

name (str) – name of param
default (object) – default value of param

Returns

Param from Django settings or default.

class vstutils.utils.Dict[source]¶: Wrapper over dict which return JSON on conversion to string.

class vstutils.utils.Executor(stdout=- 1, stderr=- 2, **environ_variables)[source]¶

Command executor with realtime output write and line handling. By default and by design executor initialize string attribute output which will be modifyed by += operator with new lines by Executor.write_output() procedure. Override the method if you want change behavior.

Executor class supports periodically (0.01 sec) handling process and execute some checks by overriding Executor.working_handler() procedure method. If you want disable this behavior override the method by None value or use UnhandledExecutor.

exception CalledProcessError(returncode, cmd, output=None, stderr=None)¶

Raised when run() is called with check=True and the process returns a non-zero exit status.

Attributes:: cmd, returncode, stdout, stderr, output

property stdout¶: Alias for output attribute, to match stderr

execute(cmd, cwd)[source]¶

Execute commands and output this.

Parameters

cmd (list) – – list of cmd command and arguments
cwd (str) – – workdir for executions

Returns

– string with full output

Return type

str

working_handler(proc)[source]¶

Additional handler for executions.

Parameters: proc (subprocess.Popen) –
Return type: None

write_output(line)[source]¶

Parameters: line (str) – – line from command output
Returns: None
Return type: None

class vstutils.utils.KVExchanger(key, timeout=None)[source]¶: Class for transmit data using key-value fast (cache-like) storage between services. Uses same cache-backend as Lock.

class vstutils.utils.Lock(id, payload=None, repeat=1, err_msg='', timeout=None)[source]¶

Lock class for multi-jobs workflow.

Note

Used django.core.cache lib and settings in settings.py
Have Lock.SCHEDULER and Lock.GLOBAL id

class vstutils.utils.ModelHandlers(type_name, err_message=None)[source]¶

Handlers for some models like ‘INTEGRATIONS’ or ‘REPO_BACKENDS’. Based on ObjectHandlers but more specific for working with models. All handlers backends get by first argument model object.

Attributes:

Parameters

objects (dict) – – dict of objects like: {<name>: <backend_class>}
keys (list) – – names of supported backends
values (list) – – supported backends classes
type_name (str) –
err_message (typing.Optional[str]) –

get_object(name, obj)[source]¶

Parameters

name (str) – – string name of backend
name – str
obj (django.db.models.Model) – – model object

Returns

backend object

Return type

object

class vstutils.utils.ObjectHandlers(type_name, err_message=None)[source]¶

Handlers wrapper for get objects from some settings structure.

Example:

from vstutils.utils import ObjectHandlers

'''
In `settings.py` you should write some structure:

SOME_HANDLERS = {
    "one": {
        "BACKEND": "full.python.path.to.module.SomeClass"
    },
    "two": {
        "BACKEND": "full.python.path.to.module.SomeAnotherClass",
        "OPTIONS": {
            "some_named_arg": "value"
        }
    }
}
'''

handlers = ObjectHandlers('SOME_HANDLERS')

# Get class handler for 'one'
one_backend_class = handlers['one']
# Get object of backend 'two'
two_obj = handlers.get_object()
# Get object of backend 'two' with overriding constructor named arg
two_obj_overrided = handlers.get_object(some_named_arg='another_value')

Parameters

type_name (str) –
err_message (typing.Optional[str]) –

backend(name)[source]¶

Get backend class

Parameters: name (str) – – name of backend type
Returns: class of backend
Return type: type,types.ModuleType,object

class vstutils.utils.Paginator(qs, chunk_size=None)[source]¶: Class for fragmenting the query for small queries.

class vstutils.utils.SecurePickling(secure_key=None)[source]¶

Secured pickle wrapper by Vigenère cipher.

Example:

from vstutils.utils import SecurePickling


serializer = SecurePickling('password')

# Init secret object
a = {"key": "value"}
# Serialize object with secret key
pickled = serializer.dumps(a)
# Deserialize object
unpickled = serializer.loads(pickled)

# Check, that object is correct
assert a == unpickled

Parameters: secure_key (typing.Optional[str]) –

class vstutils.utils.URLHandlers(type_name='GUI_VIEWS', *args, **kwargs)[source]¶

Object handler for GUI views. Uses GUI_VIEWS from settings.py. Based on ObjectHandlers but more specific to urlpatterns.

Example:

from vstutils.utils import URLHandlers


# By default gets from `GUI_VIEWS` in `settings.py`
urlpatterns = list(URLHandlers())

Parameters: type_name (str) –

get_object(name, *argv, **kwargs)[source]¶

Get url object tuple for urls.py

Parameters

name (str) – url regexp from
argv – overrided args
kwargs – overrided kwargs

Returns

url object

Return type

django.urls.re_path

class vstutils.utils.UnhandledExecutor(stdout=- 1, stderr=- 2, **environ_variables)[source]¶: Class based on Executor but disables working_handler.

class vstutils.utils.apply_decorators(*decorators)[source]¶

Decorator which apply list of decorators on method or class.

Example:

from vstutils.utils import apply_decorators

def decorator_one(func):
    print(f"Decorated {func.__name__} by first decorator.")
    return func

def decorator_two(func):
    print(f"Decorated {func.__name__} by second decorator.")
    return func

@apply_decorators(decorator_one, decorator_two)
def decorated_function():
    # Function decorated by both decorators.
    print("Function call.")

class vstutils.utils.classproperty(fget, fset=None)[source]¶

Decorator which makes class method as class property.

Example:

from vstutils.utils import classproperty

class SomeClass(metaclass=classproperty.meta):
    # Metaclass is needed for set attrs in class
    # instead of and not only object.

    some_value = None

    @classproperty
    def value(cls):
        return cls.some_value

    @value.setter
    def value(cls, new_value):
        cls.some_value = new_value

Parameters

fget (typing.Callable) –
fset (typing.Optional[typing.Callable]) –

vstutils.utils.decode(key, enc)[source]¶

Decode string from encoded by Vigenère cipher.

Parameters

key (str) – – secret key for encoding
enc (str) – – encoded string for decoding

Returns

– decoded string

Return type

str

vstutils.utils.deprecated(func)[source]¶

This is a decorator which can be used to mark functions as deprecated. It will result in a warning being emitted when the function is used.

Parameters: func (typing.Callable) –

vstutils.utils.encode(key, clear)[source]¶

Encode string by Vigenère cipher.

Parameters

key (str) – – secret key for encoding
clear (str) – – clear value for encoding

Returns

– encoded string

Return type

str

vstutils.utils.get_render(name, data, trans='en')[source]¶

Render string from template.

Parameters

name (str) – – full template name
data (dict) – – dict of rendered vars
trans (str) – – translation for render. Default ‘en’.

Returns

– rendered string

Return type

str

vstutils.utils.list_to_choices(items_list, response_type=<class 'list'>)[source]¶

Method to create django model choices from flat list of values.

Parameters

items_list (typing.Iterable) – list of flat values.
response_type (typing.Callable) – casting type of returned mapping

Return type

typing.Iterable[typing.Tuple[str, str]]

Returns

list of tuples from items_list values

class vstutils.utils.model_lock_decorator(**kwargs)[source]¶

Decorator for functions where ‘pk’ kwarg exist for lock by id.

Warning

On locked error raised Lock.AcquireLockException
Method must have and called with pk named arg.

class vstutils.utils.raise_context(*args, **kwargs)[source]¶: Context for exclude exceptions.

class vstutils.utils.raise_context_decorator_with_default(*args, **kwargs)[source]¶

Context for exclude errors and return default value.

Example:

from yaml import load
from vstutils.utils import raise_context_decorator_with_default


@raise_context_decorator_with_default(default={})
def get_host_data(yaml_path, host):
    with open(yaml_path, 'r') as fd:
        data = load(fd.read(), Loader=Loader)
    return data[host]
    # This decorator used when you must return some value even on error
    # In log you also can see traceback for error if it occur

def clone_host_data(host):
    bs_data = get_host_data('inventories/aws/hosts.yml', 'build_server')
    ...

class vstutils.utils.redirect_stdany(new_stream=<_io.StringIO object>, streams=None)[source]¶

Context for redirect any output to own stream.

Note

On context return stream object.
On exit return old streams

vstutils.utils.send_template_email(sync=False, **kwargs)[source]¶

Function executing sync or async email sending; according sync argument and settings variable “RPC_ENABLED”. You can use this function to send message, it sends message asynchronously or synchronously. If you don’t set settings for celery or don’t have celery it sends synchronously mail. If celery is installed and configured and sync argument of the function is set to False, it sends asynchronously email.

Parameters

sync (bool) – argument for determining how send email, asynchronously or synchronously
subject – mail subject.
email – list of strings or single string, with email addresses of recipients
template_name – relative path to template in templates directory, must include extension in file name.
context_data – dictionary with context for rendering message template.

vstutils.utils.send_template_email_handler(subject, email_from, email, template_name, context_data=None, **kwargs)[source]¶

Function for email sending. The function convert recipient to list and set context before sending if it possible.

Parameters

subject (str) – mail subject.
email_from (str) – sender that be setup in email.
email (typing.Union[typing.List, str]) – list of strings or single string, with email addresses of recipients
template_name (str) – relative path to template in templates directory, must include extension in file name.
context_data (typing.Optional[typing.Dict]) – dictionary with context for rendering message template.
kwargs – additional named arguments for send_mail

Return type

typing.SupportsInt

Returns

Number of emails sent.

class vstutils.utils.tmp_file(data='', mode='w', bufsize=- 1, **kwargs)[source]¶

Temporary file with name generated and auto removed on close.

Attributes:

Parameters

data (str) – – string to write in tmp file.
mode (str) – – file open mode. Default ‘w’.
bufsize (int) – – bufer size for tempfile.NamedTemporaryFile
kwargs – – other kwargs for tempfile.NamedTemporaryFile

write(wr_string)[source]¶

Write to file and flush

Parameters: wr_string (str) – – writable string
Returns: None
Return type: None

class vstutils.utils.tmp_file_context(*args, **kwargs)[source]¶

Context object for work with tmp_file. Auto close on exit from context and remove if file still exist.

This context manager over tmp_file

VST Utils documentation

Backend API manual¶

Models¶

Also you can use custom models without using database:¶

Web API¶

Fields¶

Validators¶

Serializers¶

Views¶

Filtersets¶

Responses¶

Middlewares¶

Endpoint¶

Bulk requests¶

Openapi schema¶

Testing Framework¶

Creating test case¶

Simple example with classic tests¶

Bulk requests in tests¶

Test case API¶

Utils¶